I just bought a beautiful 6mm princess cut sapphire to replace the CZ in my engagement ring. Unfortunately, I did not realize the setting is actually 7mm! Is it possible to set this smaller stone in my ring? The setting is set down in the ring shank, so the prongs are actually a part of the design.
What a crazy mistake!

I just bought a beautiful 6mm princess cut sapphire to replace the CZ in my engagement ring. Unfortunately, I did not realize the setting is actually 7mm! Is it possible to set this smaller stone in my ring? The setting is set down in the ring shank, so the prongs are actually a part of the design.
What a crazy mistake!

Can anyone tell me if I can still make this work?

The only way to make this work is to build a gold ring under your stone which is wide enough to fit in the prongs AND narrow enough on the inside diameter to allow your ring to be seated on it. The prongs would then need to be long enough to fit over your stone to hold it in place.

You might also be able to have larger prongs made to replace the existing prongs and then the stone would fit as usual in the prongs.

The downside to either method is that you will have a gap between where your stone is and where it would be if it were the correct size. I would take it to a local bench jeweler and get their opinion on a fix for this.